C This routine works only for x sorted
       function percentile(d, n, x)
           integer n 
           real x(n), d
           real percentile
           if (d .lt. x(1)) then
               percentile = 0.0
               return
           elseif (d. gt. x(n)) then
               percentile = 100.0
               return
           else
               do 100 i = 1, n
                   if (x(i) .ge. d) then
                       percentile = (i*100.0/n)
                       return
                   endif
100            continue
           endif
       end